改性分子筛异构化合成高密度燃料挂式四氢双环戊二烯

利用正硅酸四乙酯化学液相沉积方法对HY分子筛进行改性处理。采用低温N2吸附(BET)、吡啶-红外(Py-IR)及氨气-程序升温脱附(NH3-TPD)等手段,对改性HY分子筛的骨架结构、表面酸性等进行表征。使用高压反应釜,以桥式四氢双环戊二烯为原料,对改性HY分子筛异构化合成挂式四氢双环戊二烯(exo-THDCPD)的活性进行评价。结果表明:改性后HY分子筛的骨架结构基本不变,但比表面积减小,表面强酸中心数目减少;改性后HY分子筛的催化活性有所下降,而择形性能及活性明显提高;控制HY分子筛与改性剂的质量体积比(g/mL)为10∶2时,催化剂重复使用2次,反应转化率高达76.13％,exo-THDCPD收率为75.37％。
The HY molecular sieve was modified by chemical liquid deposition with Si(OC2H5)4. The low temperature N2 adsorption, Pyridine-Infrared spectra (Py-IR) and NH3-temperature programmed desorption (NH3-TPD) were employed to characterize the framework structure and surface acidity of modified HY molecular sieves. The activity of the preparation of exo-tetrahydrodicyclopentadiene (exo-THDCPD) by isomerization of endo-tetrahydrodicyclopentadiene (endo-THDCPD) over modified HY molecular sieve was evaluated in a high-pressure reactor. The results show that the framework structure of HY molecular sieve after modification is basically unchanged. However, the specific surface area and the number of strong acids sites are decreased. And the catalytic activity was reduced as well. It is also found that the shape-selectivity and catalytic lifetime of modified HY molecular sieve catalyst are increased significantly. When the ratio between HY mass and volume of Si(OEt)4 is 10∶2, the exo-THDCPD yield remains 75.37％ at conversion of 76.13％ after the second reaction